Electrosurgical Instrument

ABSTRACT

An electrosurgical instrument with first and second branches pivotably arranged at a hinge is disclosed. The hinge is formed by a support pin at the second branch and a corresponding support cavity at the first branch. At one side adjacent to the hinge location at which the support pin extends into the support cavity, a knife guide cavity is provided in the second branch for a moveable guided support of a knife. Parallel to the pivot axis defined by the hinge, the knife guide cavity is arranged adjacent to an axial end of the support pin. The hinge or the hinge location formed by the hinge at which the support pin is arranged in the support cavity is only arranged on one side of the knife guide cavity viewed in a direction parallel to the pivot axis. The respective other side is free from hinge components.

RELATED APPLICATION(S)

This application claims the benefit of European Patent Application No.19176740.9, filed May 27, 2019, the contents of which are incorporatedherein by reference as if fully rewritten herein.

TECHNICAL FIELD

The invention refers to an electrosurgical instrument that can be used,e.g. for thermofusion or coagulation, as well as a method formanufacturing the electrosurgical instrument. The electrosurgicalinstrument has two branches, each having a jaw part, wherein each jawpart comprises a tissue contact surface. Via the tissue contact surfacesa current can be conducted through biological tissue clamped in between,e.g. in order to seal the tissue.

BACKGROUND

An electrosurgical instrument with two branches supported at each otherin a hinged manner and a knife that is moveably supported in a knifeguide cavity is known from EP 2926748 A1. The two branches areconfigured in U-shape in the hinge area. Thus, each branch has two sidewalls that extend parallel and with distance to each other. In eachbranch at one side wall a support cavity and at the respective otherside wall a hollow cylindrical support pin is provided that extendstoward the outside. The two branches can be connected via two hingeswherein the support pin of one branch engages in the support cavity ofthe respective other branch. In doing so a free space is created betweenthe two hinges in which a first guide component and a second guidecomponent can be inserted to form a knife guide cavity. The two guidecomponents are connected with each other by means of a latchedconnection for forming the knife guide cavity. At one guide component aflexible web is formed that engages in one of the two hollow cylindricalsupport pins of one hinge. Due to this engagement and due to thearranging the guide components between the hinges also the two branchesare locked against an unintended release of the hinge connection.

U.S. Pat. No. 8,574,230 B2 describes an electrosurgical instrument withtwo branches that are supported at each other in a hinged manner bymeans of a hinge. The hinge has a hinge body that is torque-proofconnected with one of the two branches. At the hinge body the supportpins are present on opposite sides in order to allow a hinged support ofthe branches. The branch that is pivotably arranged relative to thehinge body comprises a knife and a knife actuation and is configuredfrom multiple parts. In order to guide the knife through the hinge, thehinge body has a slit that extends between its two support pinsorthogonal to the pivot axis. The slit is aligned with the adjacentknife guide cavity only if the branches are closed. In the open positionof the branches the slit of the hinge body is pivoted from the extensiondirection of the adjacent knife guide and thus impedes a knifeactuation. A similar device is also described in U.S. Pat. No. 8,357,159B2 and EP 2 112 909 B1.

An instrument for sealing a vessel and for separating large tissuestructures is known from EP 2 286 752 B2. Two branches are pivotablysupported at each other by means of a pivot pin. In alignment with aknife guide cavity a slot hole passes through the pivot pin in order toallow the knife to pass through along the knife guide.

In the instrument described in EP 2 040 634 B1 a support pin forpivotably supporting two branches is provided with a through hole forpassing a knife therethrough.

The instrument described in EP 1 609 430 B1 has an eccentric knife guidewith distance to a pivot axis defined by a hinge by means of which twobranches are supported in a hinged manner at each other. Thus, the knifeis eccentrically arranged relative to the pivot axis. An eccentricsupport of the knife is undesired.

U.S. Pat. No. 9,498,280 B2 discloses an instrument in which two branchesare supported at each other in a hinged manner by means of a hinge pin.The hinge pin has a through opening through which a knife actuation ispassed.

Another instrument in which a knife is guided through a pivot pin isdescribed in U.S. Pat. No. 9,498,280 B2. Other configurations ofelectrosurgical instruments are known from EP 1 372 512 B1 and AU 2014205 809 B2.

Starting from the prior art it can be considered as an object of thepresent invention to provide an instrument in which a simpleconfiguration of the knife guide on the level of the pivot axis isallowed.

SUMMARY

According to the invention the electrosurgical instrument has a firstbranch that comprises a support cavity and a second branch thatcomprises a support pin. The support pin engages the support cavity. Indoing so, a hinge is formed by means of which the first branch ispivotably supported about a pivot axis at a second branch. The pivotaxis is defined by the support pin and/or the support cavity. Atransverse direction is orientated parallel to the pivot axis.

In the second branch a knife guide cavity is provided in which a knifeis moveably supported in a guided manner in a movement direction. Theknife guide cavity extends in movement direction passing by the pivotaxis or the support pin to and into the second jaw in the distal endarea of the electrosurgical instrument. The knife guide cavity extendson the level of the support pin and the support cavity. Preferably, thepivot axis extends through the knife guide cavity. The knife guidecavity and the knife arranged therein are thus non-eccentricallyarranged relative to the pivot axis or the hinge.

In the transverse direction the support pin is arranged adjacent to theknife guide cavity on the one side, whereas the second branch is free ofany support pin or any support cavity on the other side. Thus, thesecond branch has no hinge parts on this other side. Thus, the hinge isformed only on the one side relative to the knife guide cavity, whereasthe respective other side is configured without hinge or hinge location.The knife guide cavity passes by the hinge. The knife guide cavity doesnot extend through hinge components of the hinge.

At least in the area of the hinge and from there to the distal end ofthe second branch, the knife guide cavity is arranged at an innerposition and can be limited in at least one section by the firstbranch—at least in the closed position of the branches. Thus, the knifeguide cavity is not positioned in this area at the outer side of thesecond branch facing away from the first branch.

Due to this configuration, the knife can be arranged in movementdirection on the level of the pivot axis or the hinge. An eccentricsupport of the knife is avoided. The pivot axis can extend through theknife guide cavity. However, a very simple configuration of the hinge isensured. Hinge configurations in which the knife must be passed throughthe support pin are not necessary. Also providing two separate hingesalong a common pivot axis can be avoided.

Thus, a very simple manufacturing and a good accessibility of the hingeand of the knife guide cavity are ensured in order to be able to cleanthe electrosurgical instrument after use.

Preferably only one single support pin and one single support cavity ispresent that form one single hinge and thus one single support location.

In an embodiment the first branch comprises a first abutment surfaceinto which the support cavity opens. The second branch can comprise asecond abutment surface from which the support pin extends. The twoabutment surfaces face each other and preferably directly or indirectlyabut against each other.

It is also advantageous, if the first abutment surface and/or the secondabutment surface forms a separation plane. The two branches areparticularly only hinged at each other via the one hinge. The hinge ispresent on one side of the separation plane in transverse direction. Theseparation plane preferably extends in a plane. The separation plane ispreferably orientated orthogonal to the pivot axis. The knife guidecavity can be arranged adjacent to the separation plane and canparticularly directly adjoin the separation plane.

It is advantageous, if the knife guide cavity is open toward the secondabutment surface. In doing so, the cleaning of the knife guide cavity orthe knife after use of the instrument is simplified. Preferably, theknife guide cavity is open toward the second abutment surface on bothsides of the pivot axis or the support pin with view in movementdirection of the knife.

In a preferred embodiment a transverse cavity extending in transversedirection can be provided in the second branch. The transverse cavityopens at one end in the knife guide cavity and at its opposite other endin transverse direction in an outer side of the second branch. The outerside of the second branch is preferably facing away from the firstbranch. The pivot axis extends preferably through the transverse cavity.In an embodiment the transverse cavity can be configured as slot hole.The slot hole can have a length in movement direction of the knife thatis at least as long as the diameter of the support pin.

By means of the transverse cavity the accessibility of the knife guidecavity in the area of the support pin is improved, e.g. for cleaningpurposes.

The support pin can adjoin a knife guide cavity directly with an axialend face. Particularly the support pin has no through opening that issuitable for passing a knife and that extends through the support pinbetween its two axial end faces. The support pin limits the knife guidecavity particularly at most at three sides.

In a preferred embodiment a purge opening is provided in the firstbranch. The purge opening opens at one end in the support cavity and atthe opposite other end in an outer side of the first branch. The purgeopening extends between its two ends in an extension directionsubstantially orthogonal to the pivot axis. The purge opening ispreferably open on a side facing the second branch. In one embodimentthe purge opening opens in a narrow side of the first branch.

The purge opening is arranged between its two ports along a section ofthe knife guide cavity in a predefined opened position of the branches.In this opened position the purge opening extends particularlycompletely along the section of the knife guide cavity. Through thepurge opening the access of the knife guide cavity is further improvedand the cleaning of the instrument is simplified. The predefined openposition is, for example, the completely opened position of the brancheswith the maximum opening angle between the two jaws of the branches.

Another aspect of the electrosurgical instrument refers to theelectrical connection of, and the supply of current to, the tissuecontact surfaces at each jaw of the branches. This design of theelectrosurgical instrument can be used independent of the previouslydescribed features concerning the guidance of a knife in a knife guidecavity.

The electrosurgical instrument according to this further aspect has afirst branch and a second branch. At the second branch a support pin isarranged defining a pivot axis. The first branch is pivotably supportedon this support pin. Each branch has a jaw in the distal area with viewfrom the pivot axis and a handling part with view from the pivot axis tothe proximal end of the electrosurgical instrument. An electricconnection device for an external cable is, for example, arranged at thefirst branch or at one single other location. The connection device iselectrically connected via a first conductor with a first tissue contactsurface of the first branch and via a second conductor with a secondtissue contact surface of the second branch. The two electric conductorsand the two tissue contact surfaces are electrically insulated from eachother such that different electrical potentials can be applied to thetwo tissue contact surfaces.

For example, each branch can have an electrically conductive core thatis at least partly enclosed with an electrically insulating plasticmaterial. The electrically insulating plastic material can form anelectrically insulating outer layer and can be applied on the core by aninjection molding process for example.

The second conductor is integrally formed and has a contact section withat least one contact part at its distal end. The at least one contactpart abuts at an outer surface of an electrically conductive area of thesupport pin, e.g. at a radially outward orientated circumferentialsurface or at an axially orientated ring surface. Particularly, the atleast one contact part is biased radially against the circumferentialsurface of the support pin. In doing so, an electrically conductiverotation joint between the support pin and the at least one contact partis established. In this manner an electric connection between the secondconductor in the first branch and the second tissue contact surface inthe second branch can be established. The support pin thus forms a partof the electric connection between the second conductor and the secondtissue contact surface. In the second branch the support pin can beconnected with the second tissue contact surface, e.g. via a conductivecore of the second branch. The connection between the support pin andthe second tissue contact surface in the second branch can also berealized by means of a further electric conductor or in another manner.

The radial sliding contact connection between the at least one contactpart and the support pin forms a reliable electrical connection and canbe very easily established. The second conductor including the contactsection can be produced very easily by separating the second conductorwith the contact section and with the at least one contact part of aplate, e.g. by punching, by separation with use of a laser, by water jetcutting or by an etching process. The second conductor does not need tobe further worked after separation from the plate, however, it can alsobe worked as an option. Preferably, the second conductor extends insidethe first branch completely along or inside a first extension plane.

At least in sections the two conductors can have the form or shape of astrip conductor. Analog to the second conductor the first conductor canbe configured integrally. It can also extend completely along or in anextension plane.

It is advantageous, if the first conductor and the second conductor arearranged in a common opening in the first branch. As an alternative thetwo conductors could also be arranged in respective openings separatedfrom each other. For example, the two conductors can be placed in a formtogether with an electrically conductive core for manufacturing of thesecond branch and can be overmolded with plastic or can be insertionsmolded in plastic, e.g. by an injection molding process.

It is preferred, if an electrically insulating intermediate layer isarranged between the first conductor and the second conductor. Theintermediate layer is positioned in a sandwich-like manner between thetwo conductors. The electrically insulating intermediate layer can becreated on the first conductor and/or the second conductor, e.g. by formfitting or overmolding, before the two conductors are subsequentlyconnected with each other for forming the second branch.

It is further advantageous, if an electrically insulating intermediatelayer is arranged between the second conductor and an electricallyconductive core of the first branch. This intermediate layer can alsoconcurrently form the electrically insulating intermediate layer betweenthe second conductor and the first conductor.

It is preferred, if the electrically insulating intermediate layer isfixedly applied on the second conductor, e.g. by an injection moldingprocess. The electrically insulating intermediate layer can also bejoined with the second conductor by gluing or another method. The jointbetween the second conductor, the intermediate layer applied thereon andthe first conductor is preferably only established during manufacturingof the first branch.

In an embodiment the second conductor has a conductor section with arectangular cross-section that adjoins the contact section. In apreferred embodiment the cross-section is constant with regard to itssize and/or shape.

It is also advantageous, if the second conductor comprises a connectionsection adjoining the conductor section, the connection section beingelectrically connected with the connection device or forming a part ofthe connection device. In one embodiment the connection section can be aplate-shaped extension of the conductor section.

Preferably the first conductor and/or the second conductor has arectangular cross-section at each location along its extension.

In one embodiment the contact section completely surrounds the supportpin in a circumferential direction about the pivot axis. In anotherembodiment the contact section may surround the support pin only partlyin circumferential direction, e.g. about at least 50% or at least 60% orat least 70% of the circumference.

In a preferred embodiment at least one holding part is formed at thecontact section that is elastically biased toward the support pin,wherein at each holding part a contact part or multiple contact parts orall of the contact parts are arranged. Due to the holding part beingintegrally formed with the second conductor, additional biasing meanscan be omitted in order to bias the contact part against thecircumferential surface of the support pin.

In addition, the contact section can comprise at least one support part.By means of the support part the contact section can be supported at aradially outer side at the first branch, the radially outer side beingarranged with distance opposite the support pin. For example, thesupport part can be supported at the electrically conductive core of thesecond branch via an electrically insulating intermediate layer.

It is advantageous, if a through hole is present between the at leastone support part and the at least one contact part that completelyextends through the contact section. In doing so, a clearance is createdbetween the support part and the contact part in order to springelastically bias the contact part against the support pin. The throughhole can be surrounded by the support part and/or the holding part ofthe contact section or can be open at one location.

In an embodiment the support pin has a cylindrical circumferentialsurface. At least the electrically conductive area of the support pin isformed by a cylinder skin surface. In another embodiment the support pinor the electrically conductive area of the support pin can be formed bythe skin surface of a truncated cone. Thus, the support pin can have atleast one conical section or can be completely conically configured.

If the support pin comprises at least one conical section, a pressingpart can be provided that creates an axial force parallel to the pivotaxis on the at least one contact part. Due to the electricallyconductive surface of the support pin arranged obliquely to the pivotaxis, also a radially pressing force between the at least one contactpart and the support pin is created thereby.

The electrosurgical instrument described above can be manufactured bytaking the following steps:

-   -   separating a first conductor from a plate and separating a        second conductor from a plate;    -   electrically connecting the first conductor with a first tissue        contact surface;    -   arranging of the first tissue contact surface, the first        conductor and the second conductor in a first die and creating a        first branch by inserting of a pourable, curable material in the        first die, such that the at least one contact part of a contact        section of the second conductor is arranged in a support cavity        of the first branch;    -   arranging of an electrically conductive support pin and a second        tissue contact surface electrically connected with the support        pin in a second die and creating a second branch by inserting a        pourable, curable material in the second die; and    -   inserting the support pin of the second branch in the support        cavity of the first branch for establishing the hinged joint of        the two branches at each other.

In all of the embodiments of the electrosurgical instruments that havebeen explained above, the instrument can be configured as single useinstrument or reusable instrument.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention yield from the dependent claims,the description and the drawings. In the following preferred embodimentsof the invention are explained in detail based on the attached drawings.The drawings comprise the following:

FIG. 1 shows a schematic side view of an embodiment of anelectrosurgical instrument,

FIG. 2 shows a perspective illustration of another embodiment of anelectrosurgical instrument,

FIG. 3 shows a side view of an embodiment of an electrosurgicalinstrument as well as the electric connection in a block diagram-likeillustration,

FIG. 4 shows a schematic side view of the first branch and the secondbranch of the electrosurgical instrument of FIG. 3,

FIG. 5 shows a distal end section of an electrosurgical instrument in aperspective partial illustration,

FIG. 6 shows a schematic top view of a distal end section of anelectrosurgical instrument,

FIG. 7 shows a cross-section illustration through a hinge of twobranches of the electrosurgical instrument pivotably supported at eachother, wherein the branches are shown in exploded view,

FIG. 8 shows a cross-section through the distal end section of theelectrosurgical instrument of FIG. 5 along the pivot axis in aperspective partial illustration,

FIG. 9 shows a schematic perspective partial illustration of the twobranches of the electrosurgical instrument in an opened position of thebranches,

FIG. 10 shows a perspective partial view in a section orthogonal to thepivot axis with view on a contact section of an electric secondconductor that is arranged in the first branch,

FIG. 11 shows a side view of the second electric conductor of FIG. 10,

FIGS. 12 and 13 each show a basic sketch for illustrating the electricconnection between the contact section of the second conductor and anelectrically conductive circumferential area of the support pin,

FIG. 14 shows a schematic illustration of another embodiment of thecontact section of the second conductor,

FIGS. 15-19 each show a schematic basic illustration of a configurationof a contact part of the contact section of the second conductor,

FIGS. 20-23 each show a schematic cross-section view through anembodiment of the electrosurgical instrument with differentconfigurations of the electric connection between the contact section ofthe second conductor in the first branch and the support pin in thesecond branch.

DETAILED DESCRIPTION

Each of FIGS. 1-4 shows an embodiment of an electrosurgical instrument10 that is configures as bipolar instrument according to the example.The electrosurgical instrument has a first branch 11 and a second branch12 that are pivotably arranged about a pivot axis S at each other bymeans of a hinge 13. The pivot axis S extends in a transverse directionQ.

In the embodiment illustrated in FIG. 1 from the branches 11, 12 thejaws 14, 15 are substantially shown that extend originating from thepivot axis S or the hinge 13 in a distal area. The first jaw 14 and/orthe second jaw 15 can be pivotably supported. For opening or closing thejaws 14, 15 the instrument 10 comprises a respective handling unit 16.By means of the handling unit 16 also further actions can be carriedout, e.g. the application of voltage between a first tissue contactsurface 17 at the first jaw 14 and a second tissue contact surface 18 atthe second jaw 15 or the initiating of a current flow through tissueclamped or held between the tissue contact surfaces 17, 18. Additionallyor alternatively, also a knife can be moved in a knife guide cavityalong the jaws 14, 15 to the distal end, e.g. to separate tissue clampedor held between the jaws 14, 15. The knife and the knife guidance willbe explained in greater detail later.

Additional embodiments of an electrosurgical instrument are illustratedin FIGS. 2-4 that are configured in a scissors-like manner respectively.As apparent in the figures, the first branch 11 has a first jaw 14originating from the pivot axis S in direction to the distal end and afirst handling part 19 originating from the pivot axis S in direction tothe proximal end. In accordance thereto a second branch 12 has a secondjaw 15 originating from the pivot axis S in direction toward the distalend and a second handling part 20 originating from the pivot axis S indirection to the proximal end.

For forming the hinge 13 a support pin 24 defining the pivot axis S ispresent at the second branch 12, the support pin 24 engaging in asupport cavity 25 formed at the first branch 11. The outer diameter ofthe support pin 24 corresponds—apart from a technically necessaryplay—to the inner diameter of the support cavity 25. The support pin 24extends into the support cavity 25 and thus forms the hinge 13. As forexample schematically illustrated in FIGS. 7-9, the joint between thesupport pin 24 and the support cavity 25 can be secured by means of alocking part 26 that can be connected with the free end 24 a of thesupport pin 24. The locking part 26 can have a plate-shaped form andpreferably has a circular outer contour.

As particularly illustrated in FIGS. 7 and 8, the locking part 26 ispositioned in a depression 27 provided at the first branch 11 in casethe connection is established, wherein the depression 27 expands thesupport cavity 25 on the side of the second branch 12 facing away fromthe first branch 11, such that in so doing a ring shoulder 28 is createdin the transition from the support cavity 25 to the depression 27. Ifthe connection is established, the locking part 26 abuts at the ringshoulder 28. The locking part 26 is slidingly movably supported in thedepression 27 relative to the first branch 11 according to the exampleand is torque-proof connected with the second branch 12 and according tothe example with the support pin 24.

For establishing the electric connection the instrument 10 comprises aconnection device 29 that is configured to be connected with an externalelectric connection 30 (FIGS. 3 and 4). The electric connection can beestablished by plugging the connection device 29 to the externalelectric connection 30 for example. If necessary, mechanical lockingmeans can be present in order to avoid an unintentional disconnection ofthe electrical connection.

In the embodiments of the electrosurgical instrument 10 illustrated inFIGS. 2-4 the electric connection device 29 is provided at one of thebranches and according to the example at the first branch 11. Theelectric connection device 29 is located at the proximal end of thefirst handling part 19. The electric connection device 29 is configuredat least with two poles, wherein one pole is electrically connected bymeans of a first conductor 31 with the first tissue contact surface 17and the second pole is electrically connected by means of a secondconductor 32 with the second tissue contact surface 18. The electricconnections are particularly illustrated in FIGS. 3 and 4. The firstconductor 31 forms at least a part of the electric connection betweenthe electric connection device 29 and the first tissue contact surface17. It can indeed extend originating from the connection device 29 tothe first tissue contact surface 17, however, also other electricallyconductive components of the first branch 11 can be used to establish apart of the electric connection, particularly in the first jaw 14 of thefirst branch 11.

The second conductor 32 extends originating from the connection device29 to the hinge 13. By means of the hinge 13 an electric connectionbetween the second conductor 32 and the second branch 12 is established.The further electric connection between hinge 13 and the second tissuecontact surface 18 is established in the second jaw 15 of the secondbranch 12.

As highly schematically illustrated in the perspective cut view of FIG.8, the first branch 11 and the second branch 12 can have at least in thefirst jaw 14 and the second jaw 15 an electrically conductive core 33that is at least partly enclosed by an electrically insulating outerlayer 34. The outer layer 34 is provided in the area of the respectivebranches 11, 12 in which no electric connection shall be established tothe outside. Preferably the outer layer 34 is provided everywhereoutside the hinge 13 and outside of the respective tissue contactsurfaces 17, 18. In doing so, a contact protection is created and ashort circuit between the electrically conductive parts of the branches11, 12 and particularly between the respective electrically conductivecores 33 is avoided.

As illustrated in FIGS. 2-4, the two conductors 31, 32 are arranged inthe first branch 11. They can be arranged in a common opening 38 in thefirst branch 11 (FIGS. 2 and 10). In the embodiment the two conductors31, 32 are each formed by one integral part. Each conductor 31 extendsalong an individual or a common extension plane that is orientatedorthogonal to the pivot axis S. The conductors 31, 32 can be created byseparation from a plate 39, as schematically illustrated in FIG. 11 forthe second conductor 32. The separation can be carried out by punching,laser beam cutting, water jet cutting, etching or a combination of thementioned procedures or any other separation method.

The first conductor 31 and the second conductor 32 are arranged adjacentto each other in transverse direction Q and can extend in an alignedmanner at least in sections. As illustrated in FIG. 2, the conductors31, 32 extend through the first handling part 19 predominantly in analigned manner, according to the example at least from the connectiondevice along an area of the first handling part 19, in which the firsthandling part 19 and the second handling part 20 are arranged adjacentto each other in a height direction H orthogonal to the transversedirection Q. In the hinge area the two conductors 31, 32 can at leastextend in sections in an aligned manner with view in transversedirection Q or otherwise have extensions that distinguish from eachother.

As schematically illustrated in FIG. 4, the first conductor 31 can beelectrically connected with the core 33 at a connection location 40 inthe area of the support cavity 25, e.g. by welding, soldering or gluing.The electric connection between the first connection location 40 and thefirst tissue contact surface 17 is created by the electricallyconductive core 33 of the first branch 11 or the first jaw 14. As analternative to this embodiment, the first conductor 31 could also extendcontinuously to the first tissue contact surface 17. In a furtherembodiment the connection location 40 and the first handling part 19could also be arranged farther away from the support cavity 25. This isdependent from how far an electrically conductive core 33 extends in thefirst branch 11 from the first jaw 14 in direction toward the proximalend or the electric connection device 29.

The first conductor 31 and the second conductor 32 each have aconnection section 41 that can have a substantially rectangular contour.Alternatively to this the connection section 41 can also have a roundand particularly circular cross-section. The connection section 41 is atleast partly accessible from outside the first branch 11 and serves tocreate the electric connection with the electric connection device 29.The connection sections 41 can be part of the electric connection device29.

A conductor section 42 adjoins the electric connection section 41 in thefirst conductor 31, as well as in the second conductor 32, wherein theconductor section 42 has the shape of a strip conductor. The conductorsection 42 has a rectangular cross-section. In transverse direction Qthe thickness of the conductor section 42 is less than the width inheight direction H thereof.

As already explained, the conductor section 42 of the first conductor 31can be electrically connected with the core 33 of the first branch 11 atthe connection location 40. The conductor section 42 of the secondconductor 32 has a contact section 44 at its distal end 43 that is theend opposite its connection section 41. The contact section 44 comprisesat least one and according to the example, multiple contact parts 45.The contact section 44 with the at least one contact part 45 isconfigured to establish an electric connection with an electricallyconductive area of the support pin 24. For this the at least one contactpart 45 is in contact with an outer surface and according to theexample, a circumferential surface 46 of the electrically conductivearea of the support pin 24. In the embodiment the support pin 24 is partof an electrically conductive core 33 of the second branch 12 and thuselectrically conductive as a whole. The support pin 24 is at leastpartly free from the electrically insulating outer layer 34 at itscircumferential surface, such that an electric connection with the atleast one contact part 45 of the contact section 44 can be established.

An embodiment of the contact section 44 is illustrated in FIGS. 10 and11. In this embodiment the contact section 44 completely surrounds thesupport pin 24 in a circumferential direction about the pivot axis S.The contact parts 45 are according to the example arranged with distanceto each other in circumferential direction about the pivot axis S andparticularly regularly distributed. As an alternative to thisembodiment, the contact section 44 can only partly surround the supportpin 24 in circumferential direction about the pivot axis S, preferablyabout at least 50% or at least 60% or at least 70% of the circumference.Thus, the contact section 44 can be fork-like configured as analternative to the illustrated embodiments.

The principle of electric contacting between the circumferential surface46 of the support pin 24 and the at least one contact part 45 isillustrated in FIGS. 12 and 13. Each contact part 45 can be in asubstantially line-shaped contact with the circumferential surface 46 ofthe support pin 24 parallel to the pivot axis S, as exemplarily shown inFIG. 12. Such a line-shaped contact is created, particularly if acontact part 45 comprises a curvature on the side facing thecircumferential surface 46 that does not correspond to the curvature ofthe circumferential surface 46 and can be configured in a convex orplanar manner. As an alternative to this, each contact part 45 cancomprise a concave curvature on its side facing the circumferentialsurface 46 that corresponds with the curvature of the circumferentialsurface 46 in circumferential direction about the pivot axis S, suchthat a substantially two-dimensional contact is created between thecontact part 45 and the circumferential surface 46 (FIG. 13).

As in addition shown in FIGS. 12 and 13 in a block-diagram-likeschematic manner, the at least one contact part 45 is urged radiallytoward the pivot axis S against the circumferential surface 46 of thesupport pin 24. This can be achieved, for example by an elasticdeformation of at least a part of the contact section 44. Separatebiasing means for radially biasing of the at least one contact part 45against the support pin 24 are not provided according to the example,but the radial biasing force is created by the contact section 44itself.

For this the contact section 44 comprises at least one support part 47that is supported indirectly or directly at the first branch 11 or at awall of the first branch 11 that borders the opening 38. The supportpart 47 can extend ring-shaped about the pivot axis S, as illustrated inFIGS. 10-13.

In the embodiment shown in FIGS. 10 and 11 the contact section 44comprises additionally at least one holding part 48 at which one,multiple or all of the provided contact parts 45 are arranged. Theholding part 48 is elastically biased in direction toward the supportpin 24. The biasing is created by an elastic deformation of the holdingpart 48, if the at least one contact part 45 arranged at the holdingpart 48 abuts against the circumferential surface 46 of the support pin24 and in so doing, is deflected away from the pivot axis S out of arest position. The at least one contact part 45 takes the rest positionin case the holding part 48 is not elastically deformed. Due to thedeformation of the at least one holding part 48, it is achieved that thecontact part or contact parts arranged thereon are pressed with a radialbiasing force against the circumferential surface 46.

The holding parts 48 are schematically illustrated as springs in FIGS.12 and 13. The constructive configuration of the holding parts 48 canvary.

In the embodiment illustrated in FIGS. 10 and 11 a through hole 49 isprovided between the at least one support part 47 and each holding part48 with view radial to the pivot axis S. The through hole 49 extendscompletely through the contact section 44 in transverse direction Q.According to the example, the through hole 49 has a circular arc-shapedform in circumferential direction about the pivot axis S. In theillustrated embodiment three holding parts 48 and three through holes 49adjoining thereto are provided. The through holes 49 are arranged withdistance to each other in circumferential direction about the pivot axisS. According to the example, the holding parts 48 each support onecontact part 45 in their center area in circumferential direction aboutthe pivot axis S. According to the example, the contact part 45 has acylindrical contour. Each holding part 48 thus forms a kind of leafspring, wherein the respective adjacent through holes 49 provide aradial clearance allowing an elastic deformation of the respectiveholding part 48.

Instead of a contact part 45 with a cylindrical contour, as shown in thebasic illustration in FIG. 15, the contact part 45 with a differentconfiguration can be arranged at each holding part 48. FIG. 16 shows anembodiment for a contact part 45 in which in circumferential directionabout the pivot axis S two adjacent convex curved surface sections areprovided that abut at the circumferential surface 46 of the support pin24.

The contact part 45 in the embodiment according to FIG. 17 has a surfacesection in contact with the circumferential surface 46 of the supportpin 24, the curvature of which corresponds substantially with thecurvature of the circumferential surface 46.

Alternative embodiments for holding part 48 are illustrated in FIGS. 18and 19. In these embodiments the holding part 48 is bent one time ormultiple times and can have, e.g. an L-shaped (FIG. 18) or S-shaped(FIG. 19) configuration, such that a radial clearance 50 between the atleast one contact part 45 and the support part 47 or multiple of suchclearances 50 are created. Thus, the at least one contact part 45 ismovably arranged in a spring-elastic manner radial to the pivot axis S.

A further configuration possibility for the contact section 44 is shownin FIG. 14. In this embodiment multiple support parts 47 are arrangedwith distance to each other in circumferential direction about the pivotaxis S. Two directly adjacent support parts 47 are joined with eachother by one web-shaped holding part 48. At least one contact part 45 isprovided at the holding part 48 or formed by the holding part 48. In theembodiment the web-shaped holding parts 48 are arc-shaped curved towardthe pivot axis S and abut the respective center area between the twoadjacent support parts 47 at the circumferential surface 46 of thesupport pin 24 and form at this location the contact part 45.

In the embodiments described so far the circumferential surface 46 ofthe support pin 24 is configured according to a cylinder skin surfacecoaxially to the pivot axis S. In FIGS. 20-23 alternative embodimentsfor the support pin 24 are schematically illustrated, whereinparticularly the outer surface thereof comprises different contoursand/or orientations for abutment with the contact part 45. The supportpin 24 can be conically as a whole (FIGS. 20 and 21) or can at leastcomprise a conical section (FIG. 22). The conical shape is provided suchthat the support pin 24 tapers at least in sections toward the lockingpart 26. The area in which the at least one contact part 45 of thecontact section 44 abuts is configured conically in these embodiments.The contact part 45 or the contact section 44 are illustrated in FIGS.20 and 22 only highly schematically. As in the embodiments described sofar, the contact part 45 or contact section 44 can have differentconfigurations.

A pressing part 51 is provided at the locking part 26 in thisconfiguration that presses the at least one contact part 45 axially indirection parallel to the pivot axis S against the circumferentialsurface 46 of the conical section of the support pin 24. The pressingpart 51 can be arranged at the locking part 26 and forms an individualpart that is supported at the locking part 26 or can be integrallyformed with the locking part 26. Due to the axial force on the at leastone contact part 45, also a radial force is created due to thecircumferential surface of the support pin 24 extending obliquely to thepivot axis S, wherein the radial force urges the at least one contactpart 45 against the circumferential surface 46. In this embodiment aholding part 48 in the contact section 44 that is elasticallyresiliently supported in radial direction can be omitted.

In the embodiment illustrated in FIG. 23 the outer surface of thesupport pin 24 comprises a ring surface 52 against which the at leastone contact part 45 can abut. The ring surface 52 is orientated axiallyand extends according to the example in a plane that is orientatedorthogonal to the pivot axis S. For example, the ring surface 52 can beformed by a step of the support pin 24 that forms a transition locationbetween sections of the support pin 24 that adjoin each other. Thesection with the larger diameter of the support pin 24 adjoins thesecond branch 12. A pressing part 51 can be provided at the locking part26 also in this embodiment that presses the at least one contact part 45axially in direction parallel to the pivot axis S against the ringsurface 52 of the support pin 24.

As explained above, the first conductor 31 and the second conductor 32extend in an opening 38 of the second branch 12. In order to avoidelectric contacting of the two conductors 31, 32 with each other, anelectrically insulating intermediate layer 55 is arranged between thetwo conductors 31, 32 in this embodiment (FIG. 2). The electricallyinsulating intermediate layer 55 can be preferably fixedly connectedwith one of the conductors and according to the example, with the secondconductor 32. For example, it can be connected on the second conductor32 by creating a form fit connection and/or an adhesive connection. Inan embodiment the intermediate layer 55 can be form fit connected orovermolded on the second conductor 32 or can be connected with thesecond conductor 32 by injection molding.

The intermediate layer 55 at the second conductor 32 serves, accordingto the example, also to ensure an electrical insulation between thesecond conductor 32 and the electrically conductive core 33 of the firstbranch 11. The intermediate layer 55 can enclose the second conductor 32at one or more sides, as schematically illustrated in FIG. 10. Forexample, the at least one support part 47 can be supported by means ofthe intermediate layer 55 in the opening 38 at the first branch 11.

The electrosurgical instrument 10, according to the embodimentsdescribed above, can be manufactured as follows:

The two conductors 31, 32 are separated from one plate 39 or fromdifferent plates 39, e.g. by stamping, laser beam cutting, water jetcutting, etching or the like. Preferably an electrically insulatingintermediate layer 55 is then applied on the second conductor 32, e.g.by inserting the second conductor 32 in a die and overmolding the secondconductor 32 at least partly with the electrically insulatingintermediate layer 55.

Subsequently the two conductors 31, 32 that are separated by theintermediate layer 55 are commonly placed in a first die together withan electrode that comprises the first tissue contact surface. Byinserting of pourable, curable material in the first die and subsequentcuring, the first branch 11 is created that comprises the first tissuecontact surface 17 and the two conductors 31, 32. The first branch 11 ismanufactured in the first form such that a support cavity 25 is created.

An electrically conductive support pin 24 and an electrically conductiveelectrode with the second tissue contact surface 18 is arranged in asecond die, in which pourable, curable material is inserted. A secondbranch 12 is created by curing the material. After the manufacturing ofthe two branches 11, 12 they are joined with each other in a hingedmanner by inserting the support pin 24 in the support cavity 25. Duringthe creation of the hinged joint, the at least one contact part 45 ofthe contact section 44 gets into contact with the circumferentialsurface of the electrically conductive support pin 24, such that anelectrically conductive contact between the second conductor 32 with thesupport pin 24 and via the support pin 24 with the second tissue contactsurface 18 is established.

In the preferred embodiment the electrosurgical instrument 10 only hasone single hinge 13 with one single support pin 24 and one singlesupport cavity 25 into which the support pin 24 extends.

The support cavity 25 opens in a first abutment surface 56 on a sideopposite the locking part 26. The first abutment surface 56 extends in aplane orthogonal to the pivot axis S. The first abutment surface 56 canbe provided at the outer side of an area of the electrically insulatingouter layer 34 that surrounds the core 33 of the first branch 11 (FIG.8).

A second abutment surface 57 is provided at the second branch 12 fromwhich the support pin 24 extends to its free end 24 a. The secondabutment surface 57 extends preferably in a plane orthogonal to thepivot axis S. The second abutment surface 57 can be formed by the outerside of an area of the electrically insulating outer layer 34 around thecore 33 of the second branch 12 (FIG. 8).

The first abutment surface 56 and/or the second abutment surface 57 forma separation plane T and according to the example, a planar separationplane (FIG. 7). The two abutment surfaces 56, 57 abut at each other orface each other and are arranged adjacent to each other. Preferably, thetwo abutment surfaces 56, 57 abut directly against each other. In amodified embodiment a sliding ring or the like can be alternativelyarranged between the two abutment surfaces 56, 57.

The hinge 13 formed by the support pin 24 and the support cavity 25 isarranged with view in transverse direction Q only on one side of thepreferably planar separation plane T. No hinge or hinge location ispresent on the respective other side.

The separation plane T formed by the second abutment surface 57 is notpenetrated by the first branch 11 in the circumferential area about thehinge 13. The separation plane T in this case also forms a limitationplane in the hinge area of hinge 13 through which the first branch 11does not extend.

An embodiment of the electrosurgical instrument 10 comprises a knife 60that is movably supported in a guided manner in a movement direction Borthogonal to the transverse direction Q. The movement direction Bextends parallel to the extension direction of the second branch 12. Themovement direction B can extend at least partly curved depending on theconfiguration of the jaws 14, 15.

For guiding the knife 60 a knife guide cavity 61 is present in thesecond branch 12 that comprises a rectangular cross-section according tothe example. The knife 60 can be supported on the side at the walls ofthe knife guide cavity 61. The knife guide cavity 61 has a guide section62 that extends in movement direction B in the hinge area of hinge 13and thus in the area of the support pin 24. Along this guide section 62the second branch 12 is provided with a transverse cavity 63 thatextends in transverse direction Q and is penetrated by the pivot axis S.The transverse cavity 63 opens at one end in the guide section 62 of theknife guide cavity 61 and opens at the respective other end intransverse direction Q in an outer side 64 of the second branch 12.According to the example, this outer side 64 faces away from the firstbranch 11.

In the embodiment the transverse cavity 63 is configured as a slot hole65 extending in movement direction B. The length of the transversecavity 63 or the slot hole 65 in movement direction B along the guidesection 62 of the knife guide cavity 61 is at least as long andaccording to the example, longer than the outer diameter of the supportpin 24. Through the transverse cavity 63 the accessibility to the knifeguide cavity 61 is guaranteed that is limited on the other side intransverse direction Q at least partly by an axial end face 24 b of thesupport pin 24. In the embodiment the axial end face 24 b adjoinsdirectly to the guide section 62 of the knife guide cavity 61.

The support pin 24 extends in transverse direction Q from the axial endface 24 b to the free end 24 a. Orthogonal to the pivot axis S thesupport pin 24 is configured without through openings according to theexample. At least the support pin 24 has no through opening that isaligned with the knife guide cavity 61 between its axial end face 24 band its free end 24 a. Rather it is offset in transverse direction Qfrom the knife guide cavity 61.

With view in movement direction B the knife guide cavity 61 is open onboth sides of the axial end face 24 b of the support pin 24 to thesecond abutment surface 57 and thus also to the first abutment surface56. If the branches 11, 12 are closed in case the jaws 14, 15 abut ateach other in the area of the tissue contact surfaces 17, 18, the knifeguide cavity 61 is limited in movement direction B adjacent to the axialend face 24 b of the support pin 24 by the first abutment surface 56.

As particularly apparent from FIG. 7, the axial end face 24 b of thesupport pin 24 extends according to the example in the same plane as thesecond abutment surface 57. The axial end face 24 b could also bearranged offset with reference to the second abutment surface 57. Ineach case the knife guide cavity 61 is limited in the area, in which itadjoins the axial end face 24 b of the support pin 24 on at most threesides by the support pin 24.

Because of the extension of the knife guide cavity 61 through the pivotaxis S, an eccentric arrangement of the knife 60 is avoided. Thus, theknife 60 does not execute an eccentric movement about the pivot axis Salso during a pivot movement of the branches 11, 12 relative to eachother. Because the hinge 13 is arranged only on one side with referenceto the knife guide cavity 61, a simply and cheaply producibleconfiguration of the electrosurgical instrument 10 is achieved thatallows a good accessibility to the cavities and thus also anadvantageous cleaning or sterilization.

In a preferred embodiment in addition a purge opening 70 is provided inthe first branch 11 that extends substantially orthogonal to the pivotaxis S. The purge opening 70 opens at one end in the support cavity 25and on the respective opposite end in an outer side 71 of the firstbranch 11. The purge opening 70 is arranged offset to the pivot axis Sin height direction H. It extends substantially radially to the pivotaxis S.

During a pivot movement of the two branches 11, 12 relative to eachother, the purge opening 70 executes a pivot movement about the pivotaxis S. In a predefined opened position, if the two tissue contactsurfaces 17, 18 are arranged with distance to each other, the extensiondirection of the purge opening 70 is orientated parallel to movementdirection B of the knife 60 and the purge opening 70 extends along asection of the knife guide cavity 61 as schematically illustrated inFIG. 9. In doing so, access to the knife guide cavity 61 and the knife60 arranged therein in a guided manner is improved, particularly withregard to the cleaning of the instrument 10 after its use.

The embodiments of the electrosurgical instrument 10 described above canbe combined with each other or can be independently realized from eachother. Particularly the arrangement of the knife guide cavity 61 guidingthe knife 60 offset to the side of the hinge 13 can be realizedindependently from the configuration of electric contacting of thetissue contact surfaces 17, 18 via the two conductors 31, 32. Theseaspects can be realized separately from each other.

The invention refers to an electrosurgical instrument 10 with firstbranch 11 and second branch 12. The two branches are pivotably arrangedat each other by means of a hinge 13. The hinge 13 is formed by asupport pin 24 at the second branch 12 and a corresponding supportcavity 25 at the first branch 11. Preferably one single hinge 13 withone single support cavity 25 and one single support pin 24 is provided.At one side adjacent to the hinge location at which the support pin 24extends into the support cavity 25, a knife guide cavity 61 is providedin the second branch 12 for a moveable guided support of a knife 60.Parallel to the pivot axis defined by the hinge 13, the knife guidecavity 61 is arranged adjacent and preferably directly adjoining to anaxial end of the support pin. The hinge 13 or the hinge location formedby the hinge at which the support pin 24 is arranged in the supportcavity 25 is only arranged on one side of the knife guide cavity withview in a direction parallel to the pivot axis. The respective otherside is free from hinge components and does not contain means used forpivotably supporting the two branches at each other along the pivotaxis.

LIST OF REFERENCE SIGNS

-   -   10 electrosurgical instrument    -   11 first branch    -   12 second branch    -   13 hinge    -   14 first jaw    -   15 second jaw    -   16 handling unit    -   17 first tissue contact surface    -   18 second tissue contact surface    -   19 first handling part    -   20 second handling part    -   24 support pin    -   24 a free end of the support pin    -   24 b axial end face of support pin    -   25 support cavity    -   26 locking part    -   27 depression    -   28 ring shoulder    -   29 electric connection device    -   30 external electric connection    -   31 first conductor    -   32 second conductor    -   33 core    -   34 outer layer    -   38 opening    -   39 plate    -   40 connection location    -   41 connection section    -   42 conductor section    -   43 distal end of the second conductor    -   44 contact section    -   45 contact part    -   46 circumferential surface    -   47 support part    -   48 holding part    -   49 through hole    -   50 clearance    -   51 pressing part    -   52 ring surface    -   55 intermediate layer    -   56 first abutment surface    -   57 second abutment surface    -   60 knife    -   62 knife guide cavity    -   62 guide section    -   63 transverse cavity    -   64 outer surface of the second branch    -   65 slot hole    -   70 purge opening    -   71 outer surface of the first branch    -   B movement direction    -   Q transverse direction    -   S pivot axis    -   T separation plane

1. An electrosurgical instrument (10), comprising: a first branch (11)that comprises a support cavity (25) and a second branch (12) thatcomprises a support pin (24) that extends in the support cavity (25) ofthe first branch (11), thus forming a hinge (13) by means of which thefirst branch (11) is pivotably arranged about a pivot axis (S) at thesecond branch (12), a knife guide cavity (61) provided in the secondbranch (12) in which a knife (60) is moveably supported in a movementdirection (B) in a guided manner, wherein the support pin (24) isarranged on one side of the knife guide cavity (61) in a transversedirection (Q) parallel to the pivot axis (S) and wherein the secondbranch (12) is configured without a support pin and without a supportcavity on the opposite other side of the knife guide cavity (61) in thetransverse direction (Q).
 2. The electrosurgical instrument according toclaim 1, wherein the pivot axis (S) extends through the knife guidecavity (61).
 3. The electrosurgical instrument according to claim 1,wherein the first and second branches comprise no additional supportpins or support cavities.
 4. The electrosurgical instrument according toclaim 1, wherein the first branch (11) has a first abutment surface (56)in which the support cavity (25) opens, and the second branch (12) has asecond abutment surface (57) from which the support pin (24) extends,and wherein the first and second abutment surfaces (56, 57) abut againsteach other.
 5. The electrosurgical instrument according to claim 4,wherein the first abutment surface (56) and/or the second abutmentsurface (57) form a separation plane, wherein the first and secondbranches (11, 12) are hinged at each other only by the hinge (13)arranged on one side of the separation plane (T).
 6. The electrosurgicalinstrument according to claim 4, wherein the knife guide cavity (61) isarranged adjoining the separation plane (T) or adjacent to theseparation plane (T).
 7. The electrosurgical instrument according toclaim 4, wherein the knife guide cavity (61) is open to the secondabutment surface (57).
 8. The electrosurgical instrument according toclaim 7, wherein the knife guide cavity (61) is open to the secondabutment surface (57) on either side of the support pin (24) withrespect to the movement direction (B).
 9. The electrosurgical instrumentaccording to claim 1, further comprising a transverse cavity (63) in thesecond branch (12) that extends in the transverse direction (Q) andopens in the knife guide cavity (61) at an end thereof and opens in anouter side (64) of the second branch (12) at an other end.
 10. Theelectrosurgical instrument according to claim 9, wherein the transversecavity (63) is configured as slot hole (65) having a length in movementdirection (B) that is at least as long as a diameter of the support pin(24).
 11. The electrosurgical instrument according to claim 1, whereinan area of the support pin (24) adjoining the knife guide cavity (61)delimits the knife guide cavity (61) at at most three sides.
 12. Theelectrosurgical instrument according to claim 1, further comprising apurge opening (70) in the first branch (11) that opens in the supportcavity (25) at one end of the purge opening and opens at an outer side(71) of the first branch (11) at another end of the purge opening. 13.The electrosurgical instrument according to claim 12, wherein the purgeopening (70) is open on a side facing the second branch (12).
 14. Theelectrosurgical instrument according to claim 13, wherein the purgeopening (70) extends between its two ends along a section of the knifeguide cavity (61) in an opened position of the first and second branches(11, 12).